Fiber optic cables are in widespread use. Typically, a fiber optic cable has an optical fiber that is coated with a buffer coating. An elastomeric jacket surrounds the fiber. The jacket may include a strengthening material, such as carbon fibers.
Although protected by a jacket, fiber optic cables in some environments become damaged from time to time, particularly in military fighter aircraft. Fibers installed inside the boxes on the aircraft may be in protected environments with temperature control and vibration isolation, but the optical fiber cables installed in the open aircraft environment that connect the boxes and run with electrical wires are exposed to damage. If damaged, it may be necessary or expedient to remove the damaged area and reconnect portions of the original fiber optic cable with a splice. Alternatively, it might be preferred to splice part of the original fiber optic cable to a new section of fiber optic cable.
Splicing a fiber optic cable is a difficult task, particularly in the tight confines of military fighter aircraft. Replacing a single fiber optic cable can take days or even weeks under prior art repair processes. Because of the lack of space and a potentially dirty environment, it is difficult to meet the high requirements of an optical fiber splice.
One type of splice is a mechanical type that does not employ heat, rather uses a mechanical splice assembly to hold the ends together. The length of the optical fiber protruding from the buffer must be cleaved within about one thousandth of an inch. The end faces of the cleave must be perfect, with no hackles, burrs or angles. The mechanical process is difficult, and any deviation from the required tolerances will result in the splice failing.
Fusion splices employing heat are also made to optical fibers. With a fusion splice, the fiber ends are actually melted and fused together. Optical fibers for military aircraft are made of pure silica glass, which does not soften until a high temperature, such as 1,900° C. Generating that high of a temperature in the confines of an aircraft requires an electrical arc, which can be hazardous. Also, the fusion type repair equipment is large and expensive.